External regulation of External regulation of immune responseimmune response

J. OchotnáJ. Ochotná

Causal treatmentCausal treatment

a) Stem cell transplantationa) Stem cell transplantation

       

for serious congenital disorders of the immune system (some for serious congenital disorders of the immune system (some lymphoproliferative and myeloproliferative disorders) lymphoproliferative and myeloproliferative disorders)

complications: infectious complications complications: infectious complications                     Graft-versus-host                     Graft-versus-host

obtaining stem cells - collection from shovel hip bone obtaining stem cells - collection from shovel hip bone                              - from umbilical cord blood                              - from umbilical cord blood                              - from peripheral blood after stimulation                              - from peripheral blood after stimulation with GM-CSF with GM-CSF

b) Gene therapyb) Gene therapy

with a suitable expression vector is introduced with a suitable expression vector is introduced functional gene (to replace dysfunctional gen) functional gene (to replace dysfunctional gen) into the lymphocytes or stem cells into the lymphocytes or stem cells

used as a treatment for some cases of SCID used as a treatment for some cases of SCID

Substitution treatmentSubstitution treatment autologous stem cell transplantation followingautologous stem cell transplantation following

chemotherapy and radiotherapy chemotherapy and radiotherapy

treatment with intravenous immunoglobulin treatment with intravenous immunoglobulin (derived from plasma of blood donors) (derived from plasma of blood donors)

substitution of C1 inhibitor for hereditary substitution of C1 inhibitor for hereditary angioedema angioedema

substitution of erythropoietin in patients with substitution of erythropoietin in patients with chronic renal failure chronic renal failure

substitution of G-CSF in agranulocytosis substitution of G-CSF in agranulocytosis

ImmunomodulationImmunomodulation= medical procedure to adjust the disrupted immune = medical procedure to adjust the disrupted immune

function function

Non-specific immunosuppressive therapy Non-specific immunosuppressive therapy

nonspecificnonspecific = affects not only autoreactive and = affects not only autoreactive and aloreactive aloreactive                        lymphocytes, but also other components of                        lymphocytes, but also other components of immunity immunity (risk of reduction antiinfectious and anti- (risk of reduction antiinfectious and anti- tumor immunity) tumor immunity)

used for treatment of autoimmune diseases, severe used for treatment of autoimmune diseases, severe allergic allergic conditions and for organ transplantation conditions and for organ transplantation

Non-specific immunosuppressive therapy Non-specific immunosuppressive therapy corticosteroidscorticosteroids - anti-inflammatory, immunosuppressive - anti-inflammatory, immunosuppressive

effects effects                    - blocking the activity of transcription                    - blocking the activity of transcription factors (AP-1, NF factors (AP-1, NFB) B)                    - suppress the expression of genes (IL-2,                    - suppress the expression of genes (IL-2, IL-1, phospholipase A, MHC gp II, IL-1, phospholipase A, MHC gp II, adhesion molecules) adhesion molecules)                   - inhibition of histamine release from basophils                   - inhibition of histamine release from basophils                    - higher concentrations induce apoptosis                    - higher concentrations induce apoptosis of lymfocytes of lymfocytes

immunosuppressants affecting the metabolism of DNAimmunosuppressants affecting the metabolism of DNA - cyclophosphamide - cyclophosphamide

                         - methotrexate                          - methotrexate

immunosuppressant selectively inhibiting T immunosuppressant selectively inhibiting T lymphocyteslymphocytes - immunosuppressive ATB: - immunosuppressive ATB: cyclosporine A, tacrolimus, cyclosporine A, tacrolimus, rapamycin (suppressing the expression of IL-2 and rapamycin (suppressing the expression of IL-2 and IL-2R in activated T lymphocytes) IL-2R in activated T lymphocytes)                 - monoclonal antibody anti-CD3 (Immunosuppression                 - monoclonal antibody anti-CD3 (Immunosuppression

after transplantation, treatment of rejection crises) after transplantation, treatment of rejection crises)

immunoglobulins in the immunosuppressive indicationimmunoglobulins in the immunosuppressive indication                  - Polyspecific intravenous immunoglobulins - Polyspecific intravenous immunoglobulins                    (Inhibition of B lymphocytes, antiidiotype activity,                    (Inhibition of B lymphocytes, antiidiotype activity, inhibition of cytokines, neutralization of toxins, inhibition of cytokines, neutralization of toxins, inhibition of complement activation ...) inhibition of complement activation ...)

Anti-inflammatory and antiallergic Anti-inflammatory and antiallergic treatmenttreatment

nonsteroidal anti-inflammatory drugsnonsteroidal anti-inflammatory drugs

antihistaminesantihistamines - blocking H1 receptor - blocking H1 receptor                          - reduce the expression of adhesion                          - reduce the expression of adhesion molecules molecules                          - reduce the secretion of histamine ...                         - reduce the secretion of histamine ...

inhibitors of inflammatory cytokineinhibitors of inflammatory cytokine - receptor antagonist for IL-1 - receptor antagonist for IL-1

                         - monoclonal antibodies against TNF                          - monoclonal antibodies against TNF                          - thalidomide (TNF inhibitor)                          - thalidomide (TNF inhibitor)

enzyme therapyenzyme therapy - in the enzyme mixture has a - in the enzyme mixture has a major major effect trypsin and bromelain effect trypsin and bromelain                            - anti-inflammatory                            - anti-inflammatory and immunomodulatory effects and immunomodulatory effects

Non-specific immunostimulant therapyNon-specific immunostimulant therapy synthetic immunomodulatorssynthetic immunomodulators

MethisoprinolMethisoprinol (Isoprinosine) - used in viral infections with more (Isoprinosine) - used in viral infections with more severe or relapsing course severe or relapsing course

bacterial extracts and lysatesbacterial extracts and lysates

Broncho-VaxomBroncho-Vaxom - prevention of recurrent respiratory tract infections - prevention of recurrent respiratory tract infections

RibomunylRibomunyl

products of the immune systemproducts of the immune system IL-2IL-2 - renal adenocarcinoma - renal adenocarcinoma IFNIFN, IFN, IFN - viral hepatitis, some leukemia - viral hepatitis, some leukemia ErythropoietinErythropoietin – renal failure – renal failure G-CSF, GM-CSFG-CSF, GM-CSF – neutropenia – neutropenia Transfer factorTransfer factor (blood donors leukocytes undergoing dialysis) (blood donors leukocytes undergoing dialysis) Thymus hormonesThymus hormones

                             

Antigen-specific immunomodulatory Antigen-specific immunomodulatory therapytherapy specific immunomodulationspecific immunomodulation = induce an immune = induce an immune

response or tolerance against a specific antigen response or tolerance against a specific antigen

a) active immunizationa) active immunization = use of antigen to induce an immune response = use of antigen to induce an immune response that can later protect against a pathogen bearing that can later protect against a pathogen bearing the antigen the antigen (or similar antigen)(or similar antigen)

immunization vaccines are made from inactivated immunization vaccines are made from inactivated or attenuated microorganisms or their antigens or attenuated microorganisms or their antigens (polysaccharide capsule, toxins)(polysaccharide capsule, toxins)

creates long-term immunity creates long-term immunity activate cellular and antibody immunityactivate cellular and antibody immunity administration of antigen injectable, oral administration of antigen injectable, oral prophylaxis prophylaxis risk of causing infection or anaphylactic reactions risk of causing infection or anaphylactic reactions

b) passive immunization

natural natural - transfer of - transfer of maternal antibodiesmaternal antibodies in fetal in fetal bloodblood

therapeuticallytherapeutically - the use of - the use of animal antibodiesanimal antibodies against against various toxins (snake toxins, tetanus various toxins (snake toxins, tetanus toxin, botulinum toxin) toxin, botulinum toxin)

prophylaxisprophylaxis - the - the human immunoglobulinhuman immunoglobulin from from immunized individuals (hepatitis A, immunized individuals (hepatitis A, rabies, tetanus) rabies, tetanus)                     -                     - Anti-RhD antibodiesAnti-RhD antibodies - preventing - preventing maternal immunization with RhD maternal immunization with RhD++ fetus fetus

provides a temporary (3 weeks) specific humoral provides a temporary (3 weeks) specific humoral immunity immunity

the risk of induction anaphylactic reactions the risk of induction anaphylactic reactions

c) specific immunosuppressionc) specific immunosuppression

= induction of tolerance against a specific = induction of tolerance against a specific antigen antigen

ongoing clinical studiesongoing clinical studies

induction of tolerance by oral administration of induction of tolerance by oral administration of antigen (treatment of certain autoimmune antigen (treatment of certain autoimmune diseases)diseases)

allergen immunotherapy (pollen, insect poisons) allergen immunotherapy (pollen, insect poisons)

d) vaccination against cancerd) vaccination against cancer

s a promising approach appears to immunization s a promising approach appears to immunization dendritic cells dendritic cells

Defence against Defence against

extracellular pathogensextracellular pathogens

Defence against extracellular pathogensDefence against extracellular pathogens

bacteria (gram-negative, gram-positive cocci, bacilli), bacteria (gram-negative, gram-positive cocci, bacilli), unicellular parasitesunicellular parasites

for their elimination is for their elimination is necessary opsonizationnecessary opsonization (C3b, (C3b, lectins, antibodies ...) lectins, antibodies ...)

neutrophilic granulocytesneutrophilic granulocytes are chemotactic attracting are chemotactic attracting to the site of the infection (C5a, C3a and chemotactic to the site of the infection (C5a, C3a and chemotactic products of bacteria)products of bacteria)

absorbed bacteria are destroyed by the microbicidal absorbed bacteria are destroyed by the microbicidal systems systems (products of NADP-H oxidase, hydrolytic enzymes and (products of NADP-H oxidase, hydrolytic enzymes and bactericidal substances in lysosomes) bactericidal substances in lysosomes)

phagocytes production of proinflammatory cytokines phagocytes production of proinflammatory cytokines (IL-1, IL-6, TNF) that induce an increase in (IL-1, IL-6, TNF) that induce an increase in temperature, metabolic response of the organism and temperature, metabolic response of the organism and synthesis of acute phase proteinssynthesis of acute phase proteins

in later stages of infection are stimulated antigen-in later stages of infection are stimulated antigen-specific mechanisms specific mechanisms

plasma cells initially plasma cells initially produce IgMproduce IgM isotype after isotype isotype after isotype switching produce switching produce IgG1IgG1 and and IgAIgA (opsonization) (opsonization)

sIgA protect against intestinal and respiratory sIgA protect against intestinal and respiratory infections by bacteria infections by bacteria

bacteria with a polysaccharide capsule may cause bacteria with a polysaccharide capsule may cause T-independent IgM antibody production (after the T-independent IgM antibody production (after the establishment to the bacteria activate the classical establishment to the bacteria activate the classical complement path) complement path)

after infection persist IgG, IgA (protective effect) after infection persist IgG, IgA (protective effect) and memory T and B lymphocytes and memory T and B lymphocytes

in the defense against bacterial toxins apply in the defense against bacterial toxins apply neutralizing antibodies (Clostridium tetani and neutralizing antibodies (Clostridium tetani and botulinum ...) botulinum ...)

"indirect toxins - bacterial Lipopolysaccharide "indirect toxins - bacterial Lipopolysaccharide (LPS) stimulates big number of monocytes to (LPS) stimulates big number of monocytes to release TNF, which can cause septic shock release TNF, which can cause septic shock

extracellular bacterial infections are especially at extracellular bacterial infections are especially at risk individuals with disorders in the function of risk individuals with disorders in the function of phagocytes, complement and antibody phagocytes, complement and antibody production production

Defence against Defence against

intracellular pathogensintracellular pathogens

Defense against intracellular Defense against intracellular pathogenspathogens

bacteria, fungi and unicellular parasites bacteria, fungi and unicellular parasites

intracellular parasitism is given by the ability intracellular parasitism is given by the ability of microorganisms to escape microbicidal mechanisms of microorganisms to escape microbicidal mechanisms of phagocytes of phagocytes

macrophagesmacrophages, which absorbed them, produce IL-12 → , which absorbed them, produce IL-12 → TTHH11 differentiation, production of IFNdifferentiation, production of IFN and membrane TNF → and membrane TNF → activation of macrophages and induction of iNOS activation of macrophages and induction of iNOS

plasma cells under the influence of IFNplasma cells under the influence of IFN produce produce IgG2IgG2, , immune complexes containing IgG2 bind to Fc receptors on immune complexes containing IgG2 bind to Fc receptors on macrophages and thus stimulate themmacrophages and thus stimulate them

--

in the defense against intracelular parasites, in the defense against intracelular parasites, which escape from phagolysosomes apply which escape from phagolysosomes apply TTCC lymphocyteslymphocytes

intracellular microorganisms infections are at risk intracellular microorganisms infections are at risk individuals with certain disorders of phagocytes individuals with certain disorders of phagocytes and defects of T lymphocytes and defects of T lymphocytes

Anti-viral defenceAnti-viral defence

Anti-viral defenceAnti-viral defence interferonsinterferons - in infected cells is induced production of IFN - in infected cells is induced production of IFN

and IFNand IFN (prevents viral replication and in uninfected (prevents viral replication and in uninfected cells cause the anti-virus status); IFNcells cause the anti-virus status); IFN stimulates the stimulates the conversion to activated macrophages (iNOS)conversion to activated macrophages (iNOS)

NK cellsNK cells - ADCC - ADCC (Antibody-dependent cell-mediated (Antibody-dependent cell-mediated cytotoxicity) = cytotoxic reaction depends on the cytotoxicity) = cytotoxic reaction depends on the antibodies; the NK-lymphocyte recognizes cell opsonized antibodies; the NK-lymphocyte recognizes cell opsonized with IgG by stimulation Fc receptor CD16 and then with IgG by stimulation Fc receptor CD16 and then activate cytotoxic mechanisms (degranulation)activate cytotoxic mechanisms (degranulation)

infected macrophages produce infected macrophages produce IL-12IL-12 (a strong activator (a strong activator of NK cells) of NK cells)

in the defense against cytopathic viruses mostly in the defense against cytopathic viruses mostly applied applied antibodiesantibodies::

sIgAsIgA inhibit mucosal adhesion of viruses inhibit mucosal adhesion of viruses (defense against respiratory viruses and (defense against respiratory viruses and enteroviruses) enteroviruses)

neutralizing neutralizing IgGIgG and and IgMIgM antibodies antibodies activate the classical way of complement, activate the classical way of complement, which is capable of some viruses lysiswhich is capable of some viruses lysis

IgA IgA and and IgGIgG derived in viral infection have a derived in viral infection have a preventive effect in secondary infection preventive effect in secondary infection

effector effector TTCC lymphocytes lymphocytes destroy infected cells in destroy infected cells in direct contact (granzym/perforin; FasL) and by direct contact (granzym/perforin; FasL) and by produced cytokines (lymfotoxin) produced cytokines (lymfotoxin)

some viruses after infection integrate into the host some viruses after infection integrate into the host genome, where persist for years (varicella zoster, genome, where persist for years (varicella zoster, EBV, papillomavirus) EBV, papillomavirus)

by these infections are at risk individuals with T by these infections are at risk individuals with T lymphocyte lymphocyte immunodeficiency and with combined immune immunodeficiency and with combined immune disorders disorders

increased susceptibility to herpes infections in increased susceptibility to herpes infections in individuals with dysfunction of NK cellsindividuals with dysfunction of NK cells

Defense against Defense against

multicelular parasitesmulticelular parasites

Defense against multicelular parasitesDefense against multicelular parasites

contact of mast cells, basophils and eosinophils with contact of mast cells, basophils and eosinophils with parasite antigens parasite antigens

TTHH2 stimulation under the influence of IL-4 (mast cells 2 stimulation under the influence of IL-4 (mast cells and other APC stimulated by parasite)and other APC stimulated by parasite)

TTHH2 stimulate B cells with BCR-specific parasite 2 stimulate B cells with BCR-specific parasite antigensantigens

isotype switching under the influence of IL-4 to IgE isotype switching under the influence of IL-4 to IgE

IgE bind to FcIgE bind to FcRI on mast cells and basophils RI on mast cells and basophils („antigen-specific receptors“)(„antigen-specific receptors“)

establish of multivalent antigen (multicellular establish of multivalent antigen (multicellular parasite) using the IgE to highafinity Fc receptor parasite) using the IgE to highafinity Fc receptor for IgE (Fcfor IgE (FcRI) aggregation of several molecules RI) aggregation of several molecules FcFcRI RI

initiate mast cell degranulation (cytoplasmic initiate mast cell degranulation (cytoplasmic granules mergers with the surface membrane and granules mergers with the surface membrane and release their contents) release their contents)

activation of arachidonic acid metabolism activation of arachidonic acid metabolism (leukotriene C4, prostaglandin PGD2) - (leukotriene C4, prostaglandin PGD2) - amplification of inflammatory responsesamplification of inflammatory responses

start of production of cytokines (TNF, TGFstart of production of cytokines (TNF, TGF, IL-4, , IL-4, 5,6 ...) by mast5,6 ...) by mast

in later stages are activated Tin later stages are activated THH1 and are 1 and are produced antibodies of other classesproduced antibodies of other classes

eosinophils fagocyte complexes of parasitic eosinophils fagocyte complexes of parasitic

particles with IgE via their receptors for IgE particles with IgE via their receptors for IgE

eosinophils use against parasites extracellular eosinophils use against parasites extracellular bactericidal substances released from granules bactericidal substances released from granules (eosinophil cationic protein, protease) (eosinophil cationic protein, protease)

Activation of mast cellActivation of mast cell

Tumour immunologyTumour immunology

Malignant transformationMalignant transformation failure of regulation of cell division and regulation failure of regulation of cell division and regulation

of "social" behavior of the cellsof "social" behavior of the cells the uncontrollable proliferation, dissemination to the uncontrollable proliferation, dissemination to

other tissuesother tissues mutations in protoonkogenes and antionkogenesmutations in protoonkogenes and antionkogenes

Tumor cellsTumor cells unlimited growth (loss of contact inhibition)unlimited growth (loss of contact inhibition) growth without stimulating growth factorsgrowth without stimulating growth factors immortality (cancer cells have not a limited immortality (cancer cells have not a limited

number number of generations as normal cells)of generations as normal cells)

often altered number of chromosomes as frequent often altered number of chromosomes as frequent chromosomal alterationchromosomal alteration

TSA ...TSA ...

Tumor antigensTumor antigens

a)a)Antigens specific for tumors (TSA)Antigens specific for tumors (TSA)

complexescomplexes of MHC of MHCgpgp I with abnormal fragments of I with abnormal fragments of cellular proteinscellular proteins - chemically induced tumors- chemically induced tumors - leukemia with chromosomal translocation - leukemia with chromosomal translocation

complexes of MHCcomplexes of MHC gpgp with fragments of proteins of with fragments of proteins of oncogenic virusesoncogenic viruses - tumors caused by viruses (EBV, SV40, - tumors caused by viruses (EBV, SV40, polyomavirus) polyomavirus)

abnormal forms of glycoproteinsabnormal forms of glycoproteins - sialylation of surface - sialylation of surface proteins of tumor cells proteins of tumor cells

idiotypes of myeloma and lymphomaidiotypes of myeloma and lymphoma - clonotyping TCR - clonotyping TCR and BCR and BCR

b) Antigens associated with tumors (TAA)b) Antigens associated with tumors (TAA)

present also on normal cellspresent also on normal cells differences in quantity, time and local expressiondifferences in quantity, time and local expression auxiliary diagnostic markersauxiliary diagnostic markers

1)1) onkofetal antigensonkofetal antigens on normal embryonic cells and some tumor cellson normal embryonic cells and some tumor cells -fetoprotein-fetoprotein (AFP) - hepatom (AFP) - hepatom canceroembryonal antigen (CEA) - colon cancercanceroembryonal antigen (CEA) - colon cancer

2)2) melanoma antigens melanoma antigens MAGE-1, Melan-AMAGE-1, Melan-A

3) 3) antigen HER2/neuantigen HER2/neu receptor for epithelial growth factorreceptor for epithelial growth factor mammary carcinomamammary carcinoma

4) 4) EPCAMEPCAM epithelial adhesion moleculeepithelial adhesion molecule metastasesmetastases

5) 5) differentiation antigens of leukemic cellsdifferentiation antigens of leukemic cells present on normal cells of present on normal cells of leukocytesleukocytes linage linage CALLACALLA -acute lymphoblastic leukemia (CD10 pre- -acute lymphoblastic leukemia (CD10 pre-

B cells)B cells)

Anti-tumor immune mechanismsAnti-tumor immune mechanisms

Immune controlImmune control

tumor cells normally arise in tissuestumor cells normally arise in tissues and are eliminated by and are eliminated by TT lymphocytes lymphocytes probably wrong hypothesisprobably wrong hypothesis

Defensive immune responseDefensive immune response

tumor cells are tumor cells are weakly immunogenicweakly immunogenic

occurs when tumor antigens are presented to T occurs when tumor antigens are presented to T lymphocytes lymphocytes by dendritic cells activated in the inflammatory by dendritic cells activated in the inflammatory environmentenvironment

if tumor cells are detected, in defense may be involved if tumor cells are detected, in defense may be involved non-specific mechanismsnon-specific mechanisms (neutrophilic granulocytes, (neutrophilic granulocytes, macrophages, NK cells) and macrophages, NK cells) and antigen-specific antigen-specific mechanisms mechanisms (complement activating antibodies or (complement activating antibodies or ADCC, TADCC, THH1 and T1 and TCC))

cancer-associated antigens are processed by APC cancer-associated antigens are processed by APC and recognized by T lymphocytes in complex with and recognized by T lymphocytes in complex with HLA I. HLA I. and II. class with providing costimulus and II. class with providing costimulus signalssignals

predominance of predominance of TTHH11 (IFN (IFN , TNF, TNF))

specific cell-mediated cytotoxic reactivity –specific cell-mediated cytotoxic reactivity – TTCC

activation of Tactivation of THH2 → support B lymphocytes→ 2 → support B lymphocytes→ tumor tumor specific antibodiesspecific antibodies (involved in the ADCC) (involved in the ADCC)

tumor cells are destroyed by cytotoxic tumor cells are destroyed by cytotoxic NK cellsNK cells (ADCC)(ADCC)

Mechanisms of tumor resistance to the Mechanisms of tumor resistance to the immune systemimmune system

-

high variability of tumor cellshigh variability of tumor cells

low expression of tumor antigenslow expression of tumor antigens

sialylationsialylation

tumor cells signals do not provide costimulus → T tumor cells signals do not provide costimulus → T lymphocyte anergylymphocyte anergy

some anticancer substances have a stimulating some anticancer substances have a stimulating effecteffect

production of factors inactivating T lymphocytesproduction of factors inactivating T lymphocytes

expression of FasL → T lymphocyte apoptosisexpression of FasL → T lymphocyte apoptosis

inhibition of the function or durability dendritic inhibition of the function or durability dendritic cells (NO, IL-10, TGF-cells (NO, IL-10, TGF-))